The invention relates to a circuit arrangement for radio frequency level control, comprising a level controller for forming an output signal by mixing an input signal and a feedback signal in a Gilbert cell, a sensor in a feedback path for producing a measuring signal and a reference signal from the output signal, and a variable gain amplifier in the feedback path for producing the feedback signal from the difference between measuring signal and reference signal.
From 1995 IEEE International Solid State Circuits Conference (ISSCC 95), session 8, Wireless Communications, paper TA 8.7, pp. 148, 149, 354, 112, 113, 312 is known a GSM transceiver IC with on-chip filter. The paper describes how to control the IF transmission signal in a radio frequency circuit to a level of 50 mV, in that the radio frequency mixers are operated in their maximum linear range by an amplifier.
From DE 43 38 721 A1 is known a multiband radio device comprising a mixer in a multiband receiver. This mixer is provided for a conversion to an intermediate frequency via a mixing frequency, for which purpose a Gilbert cell mixer can be used, as appropriate (column 3, lines 52-56). Set off against a ring mixer with a respective mixing symmetry, which already provides sufficient attenuation of undesired spurious responses in the receiving band, the Gilbert cell mixer may be integrated.
More particularly in battery or accumulator-operated devices (for example, handhelds for mobile radio), it is interesting to reduce the supply voltage for a reduction of the energy consumption or for other device-specific reasons, as a result of which problems may occur when the state-of-the-art Gilbert cell mixer is operated.